Detailed Description

This class is used for idle events, which are generated when the system becomes idle.

Note that, unless you do something specifically, the idle events are not sent if the system remains idle once it has become it, e.g. only a single idle event will be generated until something else resulting in more normal events happens and only then is the next idle event sent again.

If you need to ensure a continuous stream of idle events, you can either use wxIdleEvent::RequestMore method in your handler or call wxWakeUpIdle() periodically (for example from a timer event handler), but note that both of these approaches (and especially the first one) increase the system load and so should be avoided if possible.

By default, idle events are sent to all windows, including even the hidden ones because they may be shown if some condition is met from their wxEVT_IDLE (or related wxEVT_UPDATE_UI) handler. The children of hidden windows do not receive idle events however as they can't change their state in any way noticeable by the user. Finally, the global wxApp object also receives these events, as usual, so it can be used for any global idle time processing.

If sending idle events to all windows is causing a significant overhead in your application, you can call wxIdleEvent::SetMode with the value wxIDLE_PROCESS_SPECIFIED, and set the wxWS_EX_PROCESS_IDLE extra window style for every window which should receive idle events, all the other ones will not receive them in this case.

Events using this class

The following event handler macros redirect the events to member function handlers 'func' with prototypes like:

Delayed Action Mechanism

wxIdleEvent can be used to perform some action "at slightly later time". This can be necessary in several circumstances when, for whatever reason, something can't be done in the current event handler. For example, if a mouse event handler is called with the mouse button pressed, the mouse can be currently captured and some operations with it – notably capturing it again – might be impossible or lead to undesirable results. If you still want to capture it, you can do it from wxEVT_IDLE handler when it is called the next time instead of doing it immediately.

This can be achieved in two different ways: when using static event tables, you will need a flag indicating to the (always connected) idle event handler whether the desired action should be performed. The originally called handler would then set it to indicate that it should indeed be done and the idle handler itself would reset it to prevent it from doing the same action again.